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Miyamoto T. Multifunctional enzymes related to amino acid metabolism in bacteria. Biosci Biotechnol Biochem 2024; 88:585-593. [PMID: 38439669 DOI: 10.1093/bbb/zbae027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 02/29/2024] [Indexed: 03/06/2024]
Abstract
In bacteria, d-amino acids are primarily synthesized from l-amino acids by amino acid racemases, but some bacteria use d-amino acid aminotransferases to synthesize d-amino acids. d-Amino acids are peptidoglycan components in the cell wall involved in several physiological processes, such as bacterial growth, biofilm dispersal, and peptidoglycan metabolism. Therefore, their metabolism and physiological roles have attracted increasing attention. Recently, we identified novel bacterial d-amino acid metabolic pathways, which involve amino acid racemases, with broad substrate specificity, as well as multifunctional enzymes with d-amino acid-metabolizing activity. Here, I review these multifunctional enzymes and their related d- and l-amino acid metabolic pathways in Escherichia coli and the hyperthermophile Thermotoga maritima.
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Affiliation(s)
- Tetsuya Miyamoto
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
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2
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Miyamoto T, Fushinobu S, Saitoh Y, Sekine M, Katane M, Sakai-Kato K, Homma H. Novel tetrahydrofolate-dependent d-serine dehydratase activity of serine hydroxymethyltransferases. FEBS J 2024; 291:308-322. [PMID: 37700610 DOI: 10.1111/febs.16953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 08/12/2023] [Accepted: 09/06/2023] [Indexed: 09/14/2023]
Abstract
d-Serine plays vital physiological roles in the functional regulation of the mammalian brain, where it is produced from l-serine by serine racemase and degraded by d-amino acid oxidase. In the present study, we identified a new d-serine metabolizing activity of serine hydroxymethyltransferase (SHMT) in bacteria as well as mammals. SHMT is known to catalyze the conversion of l-serine and tetrahydrofolate (THF) to glycine and 5,10-methylenetetrahydrofolate, respectively. In addition, we found that human and Escherichia coli SHMTs have d-serine dehydratase activity, which degrades d-serine to pyruvate and ammonia. We characterized this enzymatic activity along with canonical SHMT activity. Intriguingly, SHMT required THF to catalyze d-serine dehydration and did not exhibit dehydratase activity toward l-serine. Furthermore, SHMT did not use d-serine as a substrate in the canonical hydroxymethyltransferase reaction. The d-serine dehydratase activities of two isozymes of human SHMT were inhibited in the presence of a high concentration of THF, whereas that of E. coli SHMT was increased. The pH and temperature profiles of d-serine dehydratase and serine hydroxymethyltransferase activities of these three SHMTs were partially distinct. The catalytic efficiency (kcat /Km ) of dehydratase activity was lower than that of hydroxymethyltransferase activity. Nevertheless, the d-serine dehydratase activity of SHMT was physiologically important because d-serine inhibited the growth of an SHMT deletion mutant of E. coli, ∆glyA, more than that of the wild-type strain. Collectively, these results suggest that SHMT is involved not only in l- but also in d-serine metabolism through the degradation of d-serine.
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Affiliation(s)
- Tetsuya Miyamoto
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
| | - Shinya Fushinobu
- Department of Biotechnology, The University of Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Japan
| | - Yasuaki Saitoh
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
| | - Masae Sekine
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
| | - Masumi Katane
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
| | - Kumiko Sakai-Kato
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
| | - Hiroshi Homma
- Graduate School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
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Lin YS, Mao WC, Yao NT, Tsai GE. Pharmacokinetics and Safety of Sodium Benzoate, a d-Amino Acid Oxidase (DAAO) Inhibitor, in Healthy Subjects: A Phase I, Open-Label Study. Clin Ther 2022; 44:1326-1335. [PMID: 36104267 DOI: 10.1016/j.clinthera.2022.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 08/10/2022] [Accepted: 08/17/2022] [Indexed: 11/24/2022]
Abstract
PURPOSE N-methyl-d-aspartate receptor (NMDAR)-mediated neurotransmission plays a critical role in cognition and memory, and d-serine is a co-agonist of the receptor. d-serine is metabolized by d-amino acid oxidase (DAAO). Sodium benzoate is a DAAO inhibitor that leads to the elevation of d-serine levels and enhances NMDAR functions as a therapeutic for wide-spectrum central nervous system (CNS) disorders, including schizophrenia and dementia. For therapeutic application of sodium benzoate in CNS disorders, we conducted a Phase I study to evaluate its safety, tolerability, and pharmacokinetic profile after single-dose oral administration in healthy volunteers. In contrast to the accumulation in the CNS, sodium benzoate has a rapid pharmacokinetic profile when measured peripherally. METHODS In this Phase I study, subjects were randomized into 4 different dose groups after a single oral administration. The pharmacokinetic parameters of sodium benzoate were assessed after exposure to 250, 500, 1000, and 2000 mg of sodium benzoate. All adverse events were investigated and recorded. FINDINGS The Cmax and AUC of sodium benzoate exhibited a higher than dose-proportional increase within the dose range from 250 to 2000 mg under fasting conditions. The slopes were 1.78 and 2.61 and the 90% CIs were 1.41 to 2.15 and 2.20 to 3.03 for Cmax and AUC, respectively. Sodium benzoate was absorbed and converted to benzoic acid rapidly, reaching Cmax after ∼0.5 hour and elimination t1/2 after ∼0.3 hour. No subjects reported adverse events that were sodium benzoate related. IMPLICATIONS The nonlinear pharmacokinetic response was observed within the dose range up to 2000 mg. Sodium benzoate treatment exhibited a favorable safety profile and was well tolerated at all dose levels. The study results serve as a foundation that should be useful for investigating efficacy and safety in the drug's subsequent clinical development. TRIAL REGISTRATION TFDA-103607047.
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Affiliation(s)
- Yen-Shan Lin
- Department of Research and Development, SyneuRx International (Taiwan) Corporation, Taipei, Taiwan
| | - Wei-Chung Mao
- Tri-Service General Hospital, Taipei, Taiwan; Cheng-Hsin General Hospital, Taipei, Taiwan
| | - Nai-Tzu Yao
- Department of Research and Development, SyneuRx International (Taiwan) Corporation, Taipei, Taiwan
| | - Guochuan Emil Tsai
- Department of Research and Development, SyneuRx International (Taiwan) Corporation, Taipei, Taiwan; UCLA School of Medicine, Los Angeles, California, USA.
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Miyamoto T, Saitoh Y, Katane M, Sekine M, Sakai-Kato K, Homma H. Characterization of human cystathionine γ-lyase enzyme activities toward D-amino acids. Biosci Biotechnol Biochem 2022; 86:1536-1542. [PMID: 36085174 DOI: 10.1093/bbb/zbac151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 08/31/2022] [Indexed: 11/14/2022]
Abstract
Various D-amino acids play important physiological roles in mammals, but the pathways of their production remain unknown except for D-serine, which is generated by serine racemase. Previously, we found that Escherichia coli cystathionine β-lyase possesses amino acid racemase activity in addition to β-lyase activity. In the present work, we evaluated the enzymatic activities of human cystathionine γ-lyase, which shares relatively high amino acid sequence identity with cystathionine β-lyase. The enzyme did not show racemase activity toward various amino acids including alanine, and lyase and dehydratase activities were highest toward L-cystathionine and L-homoserine, respectively. The enzyme also showed weak activity toward L-cysteine and L-serine but no activity toward D-amino acids. Intriguingly, the pH and temperature profiles of lyase activity were distinct from those of dehydratase activity. Catalytic efficiency was higher for lyase activity than for dehydratase activity.
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Affiliation(s)
- Tetsuya Miyamoto
- Graduate School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, Japan
| | - Yasuaki Saitoh
- Graduate School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, Japan
| | - Masumi Katane
- Graduate School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, Japan
| | - Masae Sekine
- Graduate School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, Japan
| | - Kumiko Sakai-Kato
- Graduate School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, Japan
| | - Hiroshi Homma
- Graduate School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, Japan
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Hons J, Zirko R, Vasatova M, Doubek P, Klimova B, Masopust J, Valis M, Kuca K. Impairment of Executive Functions Associated With Lower D-Serine Serum Levels in Patients With Schizophrenia. Front Psychiatry 2021; 12:514579. [PMID: 33854443 PMCID: PMC8039447 DOI: 10.3389/fpsyt.2021.514579] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 02/16/2021] [Indexed: 12/01/2022] Open
Abstract
A core symptom that is frequently linked with dysregulation of glutamatergic neurotransmission in regard to schizophrenia is impairment or damage of executive functioning as a component of cognitive deficiency. The amino acid D-serine plays the role of an endogenous coagonist at the glutamatergic N-methyl-D-aspartate (NMDA) receptor glycine modulatory site. Considerably reduced serum levels of D-serine were found in patients suffering from schizophrenia compared with healthy control participants. An increase in D-serine led to augmented cognitive functionality in patients suffering from schizophrenia who were undergoing clinical trials and given the treatment of first- and second-generation antipsychotics. The study proposed the hypothesis that the D-serine blood serum levels may be linked with the extent of executive functionality in those suffering from the mental illness in question. For the purpose of examining executive function in such patients, the Rey-Osterrieth Complex Figure, Trail Making, and Wisconsin Card Sorting tests were applied (n = 50). High-performance liquid chromatography was used to gauge the total serine and D-serine levels. The extent of damage was examined through neuropsychological tests and was found to be considerably linked to D-serine serum level and the D-serine/total serine ratio (p < 0.05) in the sample being considered. A lower average serum level of D-serine and lower D-serine/total serine ratio were observed in participants with the worst performance compared with those displaying the best performance-this was true when the patients were split into quartile groups based on their results (p < 0.05). The findings of modified D-serine serum levels and the D-serine/total serine ratio linked to the extent of damage in executive functioning indicate that serine metabolism that is coresponsible for NMDA receptor dysfunction has been changed.
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Affiliation(s)
- Jaromir Hons
- Center for Psychiatry, Regional Hospital Liberec, Liberec, Czechia.,Institute of Health Studies, Technical University of Liberec, Liberec, Czechia
| | - Rastislav Zirko
- Department of Psychiatry, Faculty of Medicine in Hradec Kralove, University Hospital Hradec Kralove and Charles University in Prague, Hradec Kralove, Czechia
| | - Martina Vasatova
- Institute of Clinical Biochemistry and Diagnostics, University Hospital Hradec Kralove and Charles University in Prague, Hradec Kralove, Czechia
| | - Pavel Doubek
- Department of Psychiatry, 1st Faculty of Medicine, General Teaching Hospital and Charles University in Prague, Prague, Czechia
| | - Blanka Klimova
- Department of Neurology, Faculty of Medicine in Hradec Kralove, University Hospital Hradec Kralove and Charles University in Prague, Hradec Kralove, Czechia
| | - Jiri Masopust
- Department of Psychiatry, Faculty of Medicine in Hradec Kralove, University Hospital Hradec Kralove and Charles University in Prague, Hradec Kralove, Czechia.,Department of Neurology, Faculty of Medicine in Hradec Kralove, University Hospital Hradec Kralove and Charles University in Prague, Hradec Kralove, Czechia
| | - Martin Valis
- Department of Neurology, Faculty of Medicine in Hradec Kralove, University Hospital Hradec Kralove and Charles University in Prague, Hradec Kralove, Czechia
| | - Kamil Kuca
- Biomedical Research Center, University Hospital Hradec Kralove, Hradec Kralove, Czechia.,Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czechia
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Phenotype microarrays reveal metabolic dysregulations of neurospheres derived from embryonic Ts1Cje mouse model of Down syndrome. PLoS One 2020; 15:e0236826. [PMID: 32730314 PMCID: PMC7392322 DOI: 10.1371/journal.pone.0236826] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 07/14/2020] [Indexed: 11/20/2022] Open
Abstract
Down syndrome (DS), is the most common cause of intellectual disability, and is characterized by defective neurogenesis during perinatal development. To identify metabolic aberrations in early neurogenesis, we profiled neurospheres derived from the embryonic brain of Ts1Cje, a mouse model of Down syndrome. High-throughput phenotypic microarray revealed a significant decrease in utilisation of 17 out of 367 substrates and significantly higher utilisation of 6 substrates in the Ts1Cje neurospheres compared to controls. Specifically, Ts1Cje neurospheres were less efficient in the utilisation of glucose-6-phosphate suggesting a dysregulation in the energy-producing pathway. T Cje neurospheres were significantly smaller in diameter than the controls. Subsequent preliminary study on supplementation with 6-phosphogluconic acid, an intermediate of glucose-6-phosphate metabolism, was able to rescue the Ts1Cje neurosphere size. This study confirmed the perturbed pentose phosphate pathway, contributing to defects observed in Ts1Cje neurospheres. We show for the first time that this comprehensive energetic assay platform facilitates the metabolic characterisation of Ts1Cje cells and confirmed their distinguishable metabolic profiles compared to the controls.
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Kohiki T, Kato Y, Nishikawa Y, Yorita K, Sagawa I, Denda M, Inokuma T, Shigenaga A, Fukui K, Otaka A. Elucidation of inhibitor-binding pockets ofd-amino acid oxidase using docking simulation and N-sulfanylethylanilide-based labeling technology. Org Biomol Chem 2017; 15:5289-5297. [DOI: 10.1039/c7ob00633k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Binding pockets of a schizophrenia-relatedd-amino acid oxidase to its inhibitor were clarified by docking simulation and protein labeling experiments.
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Affiliation(s)
- Taiki Kohiki
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
| | - Yusuke Kato
- Division of Enzyme Pathophysiology
- The Institute for Enzyme Research (KOSOKEN)
- Tokushima University
- Tokushima 770-8503
- Japan
| | - Yusuke Nishikawa
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
| | - Kazuko Yorita
- Division of Enzyme Pathophysiology
- The Institute for Enzyme Research (KOSOKEN)
- Tokushima University
- Tokushima 770-8503
- Japan
| | - Ikuko Sagawa
- Support Center for Advanced Medical Sciences
- Institute of Biomedical Sciences
- Tokushima University Graduate School
- Tokushima 770-8505
- Japan
| | - Masaya Denda
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
| | - Tsubasa Inokuma
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
| | - Akira Shigenaga
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
- PRESTO
| | - Kiyoshi Fukui
- Division of Enzyme Pathophysiology
- The Institute for Enzyme Research (KOSOKEN)
- Tokushima University
- Tokushima 770-8503
- Japan
| | - Akira Otaka
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
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Horak J, Gerhardt H, Theiner J, Lindner W. Correlation between amino acid racemization and processing conditions for various wheat products, oil seed press cakes and lignin samples. FOOD AND BIOPRODUCTS PROCESSING 2014. [DOI: 10.1016/j.fbp.2013.10.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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9
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Fradi I, Farcas E, Saïd AB, Yans ML, Lamalle C, Somsen GW, Prior A, de Jong GJ, Kallel M, Crommen J, Servais AC, Fillet M. In-capillary derivatization with (-)-1-(9-fluorenyl)ethyl chloroformate as chiral labeling agent for the electrophoretic separation of amino acids. J Chromatogr A 2014; 1363:338-47. [PMID: 25082527 DOI: 10.1016/j.chroma.2014.07.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/03/2014] [Accepted: 07/09/2014] [Indexed: 11/25/2022]
Abstract
An original micellar electrokinetic chromatography (MEKC) method using in-capillary derivatization with a chiral labeling reagent was developed for the separation of amino acid (AA) derivatives. The potential of (-)-1-(9-fluorenyl)-ethyl chloroformate (FLEC) as in-capillary derivatization agent is described for the first time. Several parameters for in-capillary derivatization and subsequent MEKC separation were systematically investigated using experimental designs. Firstly experimental conditions for in-capillary derivatization were optimized using face-centered central composite design (FCCD). Mixing voltage and time as well as concentration of the labeling solution were investigated. Efficient labeling was achieved by sequential injection of AAs and FLEC labeling solution followed by the application of a voltage of 0.2 kV for 570 s. The background electrolyte (BGE) composition was then optimized in order to achieve selectivity. A FCCD was performed with two factors, namely the sodium dodecyl sulfate (SDS) concentration and the percentage of propan-2-ol (IPA). The separation of 12 pairs of derivatized AA (FLEC-AA) diastereomers was achieved with resolution values comprised between 3 and 20. Furthermore, an efficient derivatization and separation of 29 FLEC-AA derivatives were achieved in a single run using a buffer made up of 40 mM sodium tetraborate, 21 mM SDS and 8.5% IPA. The method was successfully applied to the analysis of spiked artificial cerebrospinal fluid (aCSF) sample.
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Affiliation(s)
- Ines Fradi
- Laboratory of Analytical Pharmaceutical Chemistry, Dept. of Pharmaceutical Sciences, CIRM, University of Liège, CHU, B36, B-4000 Liège 1, Belgium; Laboratory of Chemical, Galenical and Pharmacological Drug Development, Faculty of Pharmacy, University of Monastir, 5000 Monastir, Tunisia; Drug Control National Laboratory, Tunis, Tunisia
| | - Elena Farcas
- Laboratory of Analytical Pharmaceutical Chemistry, Dept. of Pharmaceutical Sciences, CIRM, University of Liège, CHU, B36, B-4000 Liège 1, Belgium
| | - Azza Ben Saïd
- Laboratory of Chemical, Galenical and Pharmacological Drug Development, Faculty of Pharmacy, University of Monastir, 5000 Monastir, Tunisia
| | - Marie-Laure Yans
- Laboratory of Analytical Pharmaceutical Chemistry, Dept. of Pharmaceutical Sciences, CIRM, University of Liège, CHU, B36, B-4000 Liège 1, Belgium
| | - Caroline Lamalle
- Laboratory of Analytical Pharmaceutical Chemistry, Dept. of Pharmaceutical Sciences, CIRM, University of Liège, CHU, B36, B-4000 Liège 1, Belgium
| | - Govert W Somsen
- Department of Chemistry and Pharmaceutical Sciences, University of Amsterdam, The Netherlands
| | - Amir Prior
- Department of Chemistry and Pharmaceutical Sciences, University of Amsterdam, The Netherlands
| | - Gerhardus J de Jong
- Department of Chemistry and Pharmaceutical Sciences, University of Amsterdam, The Netherlands
| | - Mohamed Kallel
- Laboratory of Chemical, Galenical and Pharmacological Drug Development, Faculty of Pharmacy, University of Monastir, 5000 Monastir, Tunisia
| | - Jacques Crommen
- Laboratory of Analytical Pharmaceutical Chemistry, Dept. of Pharmaceutical Sciences, CIRM, University of Liège, CHU, B36, B-4000 Liège 1, Belgium
| | - Anne-Catherine Servais
- Laboratory of Analytical Pharmaceutical Chemistry, Dept. of Pharmaceutical Sciences, CIRM, University of Liège, CHU, B36, B-4000 Liège 1, Belgium
| | - Marianne Fillet
- Laboratory of Analytical Pharmaceutical Chemistry, Dept. of Pharmaceutical Sciences, CIRM, University of Liège, CHU, B36, B-4000 Liège 1, Belgium.
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Iyyathurai J, D'hondt C, Wang N, De Bock M, Himpens B, Retamal MA, Stehberg J, Leybaert L, Bultynck G. Peptides and peptide-derived molecules targeting the intracellular domains of Cx43: gap junctions versus hemichannels. Neuropharmacology 2013; 75:491-505. [PMID: 23664811 DOI: 10.1016/j.neuropharm.2013.04.050] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 04/17/2013] [Accepted: 04/18/2013] [Indexed: 12/15/2022]
Abstract
About a decade ago, the molecular determinants controlling the opening and closing of Cx43 gap junction channels have been identified. Advanced biophysical approaches revealed a critical role for structural rearrangements in the cytoplasmic loop and dimerization of the C-terminal tail, resulting in binding of the C-terminal tail to the cytoplasmic loop and Cx43 gap junction channel closure during cellular acidosis. This has spurred the development of Cx43-mimetic peptides and peptidomimetics that interfere with these loop/tail interactions, thereby preventing the closure of Cx43 gap junctions, e.g. in the heart upon ischemia. Recently, we found that loop/tail interactions control Cx43-hemichannel activity but with an opposite effect. Binding of the C-terminal tail to the cytoplasmic loop is a requisite for the opening of Cx43 hemichannels in response to different stimuli, like decreased extracellular [Ca2+], increased intracellular [Ca2+], positive membrane potentials or ischemia. Strikingly, peptides that favor the open state of Cx43 gap junctions like the L2 peptide inhibit Cx43-hemichannel opening. These tools now provide unprecedented opportunities to selectively inhibit Cx43 hemichannels while maintaining Cx43 gap junction communication, impossible to achieve with siRNA or knockdown approaches both affecting gap junctions and hemichannels. These tools not only are very helpful to unravel the role of Cx43 hemichannels in complex biological systems, but also hold therapeutic potential to counteract excessive Cx43-hemichannel activity like in ischemia/reperfusion in the brain and the heart or to prevent Cx43 hemichannel-mediated gliotransmitter release in the basal amygdala during memory consolidation in response to emotional events. This article is part of the Special Issue Section entitled 'Current Pharmacology of Gap Junction Channels and Hemichannels'.
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Affiliation(s)
- Jegan Iyyathurai
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Catheleyne D'hondt
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Nan Wang
- Faculty of Medicine and Health Sciences, Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B-Rm 310), B-9000 Ghent, Belgium
| | - Marijke De Bock
- Faculty of Medicine and Health Sciences, Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B-Rm 310), B-9000 Ghent, Belgium
| | - Bernard Himpens
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Mauricio A Retamal
- Departamento de Fisiología, Facultad de Medicina, Clínica Alemana-Universidad del Desarrollo, Santiago, Chile
| | - Jimmy Stehberg
- Universidad Andres Bello, Laboratorio de Neurobiologia, Departamento de Ciencias Biologicas, Facultad de Ciencias Biologicas & Facultad de Medicina, Santiago, Chile; Universidad Andres Bello, Centro de Investigaciones Biomédicas, Santiago, Chile
| | - Luc Leybaert
- Faculty of Medicine and Health Sciences, Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B-Rm 310), B-9000 Ghent, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium.
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Filali M, Lalonde R. The effects of subchronic d-serine on left–right discrimination learning, social interaction, and exploratory activity in APPswe/PS1 mice. Eur J Pharmacol 2013; 701:152-8. [DOI: 10.1016/j.ejphar.2012.12.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/12/2012] [Accepted: 12/19/2012] [Indexed: 10/27/2022]
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12
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Chemo- and enantio-selective method for the analysis of amino acids by capillary electrophoresis with in-capillary derivatization. J Chromatogr A 2012; 1267:121-6. [PMID: 22727557 DOI: 10.1016/j.chroma.2012.05.098] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 05/28/2012] [Accepted: 05/29/2012] [Indexed: 11/20/2022]
Abstract
A novel dual chiral CE method was developed for the separation of l- and d-amino acids (AAs), using in-capillary derivatization with 9-fluoroenylmethyl chloroformate (FMOC). Firstly, using pre-column derivatization, the enantioseparation of FMOC-AAs was optimized according to the nature of cyclodextrins (CD). A background electrolyte (BGE) composed of 30 mM β-CD, 30 mM octakis(2,3-dihydroxy-6-O-sulfo)-γ-CD (OS-γ-CD), 40 mM tetraborate and 15% isopropanol (IPA) was selected and led to 17 baseline resolved pairs (R(s)=1.7-5.8) and two partially resolved pairs (Lys, R(s)=0.5 and Arg, R(s)=1.2). Experimental conditions for in-capillary derivatization were then optimized. Several parameters, such as mixing voltage and time, concentration of labeling solution and the length of the spacer plug were studied. The optimal conditions for in-capillary derivatization procedure were obtained using successive hydrodynamic injections (30 mbar) of AAs for 2s, borate buffer for 4s and 10mM FMOC solution for 6s, followed by a mixing at 3 kV for 72 s and wait time of 1 min. Moreover, a particular attention was paid to improve separation chemoselectivity. The effect on stereoselectivity and chemoselectivity of different factors, such as decrease of pH and tetraborate concentration and the addition of sodium dodecyl sulfate (SDS), was investigated using the in-capillary derivatization procedure. The best separation of a standard mixture of ten AA racemates was observed using a BGE containing 30 mM β-CD, 30 mM OS-γ-CD, 25 mM SDS, 40 mM sodium tetraborate and 17% IPA.
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Huang X, Kong H, Tang M, Lu M, Ding JH, Hu G. D-Serine regulates proliferation and neuronal differentiation of neural stem cells from postnatal mouse forebrain. CNS Neurosci Ther 2012; 18:4-13. [PMID: 22280157 DOI: 10.1111/j.1755-5949.2011.00276.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND AND PURPOSE D-Serine, the endogenous co-agonist of N-methyl-D-aspartate (NMDA) receptors, has been recognized as an important gliotransmitter in the mammalian brain. D-serine has been shown to prevent psychostimulant-induced decrease in hippocampal neurogenesis. However, the mechanism whereby D-serine regulates neurogenesis has not been fully characterized. Therefore, this study was designed to investigate the impacts of D-serine on the proliferation, migration, and differentiation of primary cultured neural stem cells (NSCs). METHODS AND RESULTS Immunohistochemistry analysis revealed NSCs expressed D-serine as well as serine racemase (SR). Degradation of endogenous D-serine with D-amino acid oxidase (DAAO) significantly inhibited the proliferation and neuronal differentiation of NSCs, but failed to affect their radial migration. Reversely, addition of exogenous D-serine did not affect the proliferation and migration of NSCs, but promoted NSC differentiation into neurons. Furthermore, DAAO could suppress the amplitude of glutamate-induced Ca(2+) transient, and thereby, inhibited the phosphorylation of glycogen synthase kinase3β (GSK3β), extracellular signal-regulated kinases1/2 (ERK1/2), and cAMP-responsive element-binding protein (CREB). CONCLUSIONS Our findings demonstrate for the first time that NSCs can synthesize D-serine and, thereby, promote themselves proliferation and neuronal differentiation, which may afford a novel therapeutic strategy for the neurological disorders that require nerve cell replenishment, such as neurodegenerative diseases and stroke.
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Affiliation(s)
- Xu Huang
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Jiangsu, China
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14
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Spatiotemporal localization of D-amino acid oxidase and D-aspartate oxidases during development in Caenorhabditis elegans. Mol Cell Biol 2012; 32:1967-83. [PMID: 22393259 DOI: 10.1128/mcb.06513-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Recent investigations have shown that a variety of D-amino acids are present in living organisms and that they possibly play important roles in physiological functions in the body. D-Amino acid oxidase (DAO) and D-aspartate oxidase (DDO) are degradative enzymes stereospecific for D-amino acids. They have been identified in various organisms, including mammals and the nematode Caenorhabditis elegans, although the significance of these enzymes and the relevant functions of D-amino acids remain to be elucidated. In this study, we investigated the spatiotemporal localization of C. elegans DAO and DDOs (DDO-1, DDO-2, and DDO-3) and measured the levels of several D- and L-amino acids in wild-type C. elegans and four mutants in which each gene for DAO and the DDOs was partially deleted and thereby inactivated. Furthermore, several phenotypes of these mutant strains were characterized. The results reported in this study indicate that C. elegans DAO and DDOs are involved in egg-laying events and the early development of C. elegans. In particular, DDOs appear to play important roles in the development and maturation of germ cells. This work provides novel and useful insights into the physiological functions of these enzymes and D-amino acids in multicellular organisms.
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Abstract
D-Amino acids play important physiological roles in the mammalian body. Recent investigations revealed that, in mammals, D-amino acids are synthesized from their corresponding L-enantiomers via amino acid racemase. This article describes a method used to measure amino acid racemase activity by high-performance liquid chromatography (HPLC). The assay involves fluorogenic chiral derivatization of amino acids with a newly developed reagent, and enantioseparation of D- and L-amino acid derivatives by HPLC. The method is accurate and reliable, and can be automated using a programmable autosampling injector.
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Affiliation(s)
- Masumi Katane
- Department of Pharmaceutical Life Sciences, Kitasato University, Minatoku, Tokyo, Japan
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Katane M, Homma H. D-Aspartate--an important bioactive substance in mammals: a review from an analytical and biological point of view. J Chromatogr B Analyt Technol Biomed Life Sci 2011; 879:3108-21. [PMID: 21524944 DOI: 10.1016/j.jchromb.2011.03.062] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 03/23/2011] [Accepted: 03/30/2011] [Indexed: 01/08/2023]
Abstract
It was long believed that D-amino acids were either unnatural isomers or laboratorial artifacts and that the important functions of amino acids were exerted only by l-amino acids. However, recent investigations have shown that a variety of D-amino acids are present in mammals and that they play important roles in physiological functions in the body. Among the free d-amino acids that have been identified in mammals, D-aspartate (D-Asp) has been shown to play a crucial role in the neuroendocrine and endocrine systems as well as in the central nervous system. Here, we present an overview of recent studies of free D-Asp, focusing on the analytical methods in real biological matrices, expression and localization in tissues and cells, biological and physiological activities, biosynthesis, degradation, cellular transport, and possible relevance to disease. In addition to frequently used techniques for the enantiomeric determination of amino acids, including high-performance liquid chromatography and enzymatic methods, the recent development of analytical methods is also described.
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Affiliation(s)
- Masumi Katane
- Laboratory of Biomolecular Science, Department of Pharmaceutical Life Sciences, Kitasato University, 5-9-1 Shirokane, Tokyo 108-8641, Japan
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Lin CH, Lane HY, Tsai GE. Glutamate signaling in the pathophysiology and therapy of schizophrenia. Pharmacol Biochem Behav 2011; 100:665-77. [PMID: 21463651 DOI: 10.1016/j.pbb.2011.03.023] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 03/14/2011] [Accepted: 03/28/2011] [Indexed: 11/26/2022]
Abstract
Glutamatergic neurotransmission, particularly through the N-methyl-d-aspartate (NMDA) receptor, has drawn attention for its role in the pathophysiology of schizophrenia. This paper reviews the neurodevelopmental origin and genetic susceptibility of schizophrenia relevant to NMDA neurotransmission, and discusses the relationship between NMDA hypofunction and different domains of symptom in schizophrenia as well as putative treatment modality for the disorder. A series of clinical trials and a meta-analysis which compared currently available NMDA-enhancing agents suggests that glycine, d-serine, and sarcosine are more efficacious than d-cycloserine in improving the overall psychopathology of schizophrenia without side effect or safety concern. In addition, enhancing glutamatergic neurotransmission via activating the AMPA receptor, metabotropic glutamate receptor or inhibition of d-amino acid oxidase (DAO) is also reviewed. More studies are needed to determine the NMDA vulnerability in schizophrenia and to confirm the long-term efficacy, functional outcome, and safety of these NMDA-enhancing agents in schizophrenic patients, particularly those with refractory negative and cognitive symptoms, or serious adverse effects while taking the existing antipsychotic agents.
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Affiliation(s)
- Chieh-Hsin Lin
- Department of Psychiatry, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan
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18
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Katane M, Saitoh Y, Hanai T, Sekine M, Furuchi T, Koyama N, Nakagome I, Tomoda H, Hirono S, Homma H. Thiolactomycin inhibits d-aspartate oxidase: A novel approach to probing the active site environment. Biochimie 2010; 92:1371-8. [DOI: 10.1016/j.biochi.2010.06.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 06/25/2010] [Indexed: 12/27/2022]
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19
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Katane M, Saitoh Y, Maeda K, Hanai T, Sekine M, Furuchi T, Homma H. Role of the active site residues arginine-216 and arginine-237 in the substrate specificity of mammalian D-aspartate oxidase. Amino Acids 2010; 40:467-76. [PMID: 20567862 DOI: 10.1007/s00726-010-0658-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 06/08/2010] [Indexed: 10/19/2022]
Abstract
D-aspartate oxidase (DDO) and D-amino acid oxidase (DAO) are flavin adenine dinucleotide-containing flavoproteins that catalyze the oxidative deamination of D-amino acids. Unlike DAO, which acts on several neutral and basic D-amino acids, DDO is highly specific for acidic D-amino acids. Based on molecular modeling and simulated annealing docking analyses, a recombinant mouse DDO carrying two substitutions (Arg-216 to Leu and Arg-237 to Tyr) was generated (R216L-R237Y variant). This variant and two previously constructed single-point mutants of mouse DDO (R216L and R237Y variants) were characterized to investigate the role of Arg-216 and Arg-237 in the substrate specificity of mouse DDO. The R216L-R237Y and R216L variants acquired a broad specificity for several neutral and basic D-amino acids, and showed a considerable decrease in activity against acidic D-amino acids. The R237Y variant, however, did not show any additional specificity for neutral or basic D-amino acids and its activity against acidic D-amino acids was greatly reduced. The kinetic properties of these variants indicated that the Arg-216 residue is important for the catalytic activity and substrate specificity of mouse DDO. However, Arg-237 is, apparently, only marginally involved in substrate recognition, but is important for catalytic activity. Notably, the substrate specificity of the R216L-R237Y variant differed significantly from that of the R216L variant, suggesting that Arg-237 has subsidiary effects on substrate specificity. Additional experiments using several DDO and DAO inhibitors also suggested the involvement of Arg-216 in the substrate specificity and catalytic activity of mouse DDO and that Arg-237 is possibly involved in substrate recognition by this enzyme. Collectively, these results indicate that Arg-216 and Arg-237 play crucial and subsidiary role(s), respectively, in the substrate specificity of mouse DDO.
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Affiliation(s)
- Masumi Katane
- Laboratory of Biomolecular Science, Department of Pharmaceutical Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
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Katane M, Saitoh Y, Seida Y, Sekine M, Furuchi T, Homma H. Comparative Characterization of Three D-Aspartate Oxidases and One D-Amino Acid Oxidase from Caenorhabditis elegans. Chem Biodivers 2010; 7:1424-34. [DOI: 10.1002/cbdv.200900294] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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21
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The response to postnatal stress: amino acids transporters and PKC activity. Neurochem Res 2010; 35:967-75. [PMID: 20306295 DOI: 10.1007/s11064-010-0153-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2010] [Indexed: 10/19/2022]
Abstract
It is well known that animals exposed to stressful stimuli during their early life develop different neurological disorders when they become adults. In this study, we evaluated the effect of acute cold stress on gamma-aminobutyric acid (GABA) and L-Serine (L-Ser) transporters in vitro, using the uptake of [(3)H]-GABA and [(3)H]L-Ser by synaptosomes-enriched fractions isolated from rat cerebral cortex during postnatal development. GABA and L-Ser uptake studies in vitro will be used in this investigation as a colateral evidence of changes in the expression of transporters of GABA and L-Ser. We observed that the maximum velocity (V (max)) in L-Ser and GABA uptake after stress session increased in all stages studied. In contrast, K (m) values of L-Ser uptake enhancent in almost age calculated, excluding at PD21 after cold stress during development, at the same time as K (m) (uptake affinity) values of GABA increased in just about age considered but not at PD5 compared with the control group. Finally we investigated the mechanism by which cells regulate the substrate affinity of L-Ser and GABA transporters. We demonstrated a significantly increase in total PKC activity to PD5 from PD21. Pretreatment with PKC inhibitor: staurosporine (SP) led to a restoration of control uptake in several postnatal-days suggesting a relationship between amino acids system and PKC activation. These findings suggest that a single exposure to postnatal cold stress at different periods after birth modifies both GABA and L-Ser transporters and the related increase in total PKC activity could be intracellular events that participate in neuronal plasticity by early life stress, which could be relevant to function of transporters in the adult rat brain.
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Singer HS, Morris C, Grados M. Glutamatergic modulatory therapy for Tourette syndrome. Med Hypotheses 2009; 74:862-7. [PMID: 20022434 DOI: 10.1016/j.mehy.2009.11.028] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Accepted: 11/22/2009] [Indexed: 01/11/2023]
Abstract
Tourette syndrome (TS) is a neuropsychiatric disorder characterized by the presence of chronic, fluctuating motor and vocal (phonic) tics. The disorder is commonly associated with a variety of comorbidities including obsessive-compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), school problems, anxiety, and depression. Therapeutically, if tics are causing psychosocial or physical problems, symptomatic medications are often prescribed, typically alpha-adrenergic agonists or dopamine antagonists. Recognizing that therapy is often ineffective and frequently associated with unacceptable side-effects, there is an ongoing effort to identify new tic-suppressing therapies. Several lines of evidence are presented that support the use of glutamate modulators in TS including glutamate's major role in cortico-striatal-thalamo-cortical circuits (CSTC), the recognized extensive interaction between glutamate and dopamine systems, results of familial genetic studies, and data from neurochemical analyses of postmortem brain samples. Since insufficient data is available to determine whether TS is definitively associated with a hyper- or hypo-glutamatergic state, potential treatment options using either glutamate antagonists or agonists are reviewed. Data from studies using these agents in the treatment of OCD are presented. If validated, modulation of the glutamate system could provide a valuable new pharmacological approach in the treatment of tics associated with Tourette syndrome.
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Affiliation(s)
- Harvey S Singer
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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23
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Zanatta A, Schuck PF, Viegas CM, Knebel LA, Busanello ENB, Moura AP, Wajner M. In vitro evidence that D-serine disturbs the citric acid cycle through inhibition of citrate synthase activity in rat cerebral cortex. Brain Res 2009; 1298:186-93. [PMID: 19733154 DOI: 10.1016/j.brainres.2009.08.080] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 08/20/2009] [Accepted: 08/25/2009] [Indexed: 11/16/2022]
Abstract
The present work investigated the in vitro effects of D-serine (D-Ser) on important parameters of energy metabolism in cerebral cortex of young rats. The parameters analyzed were CO(2) generation from glucose and acetate, glucose uptake and the activities of the respiratory chain complexes I-IV, of the citric acid cycle enzymes citrate synthase, aconitase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, fumarase and malate dehydrogenase and of creatine kinase and Na(+),K(+)-ATPase. Our results show that D-Ser significantly reduced CO(2) production from acetate, but not from glucose, reflecting an impairment of the citric acid cycle function. Furthermore, D-Ser did not affect glucose uptake. We also observed that the activity of the mitochondrial enzyme citrate synthase from mitochondrial preparations and purified citrate synthase was significantly inhibited by D-Ser, whereas the other activities of the citric acid cycle as well as the activities of complexes I-III, II-III, II and IV of the respiratory chain, creatine kinase and Na(+),K(+)-ATPase were not affected by this D-amino acid. We also found that L-serine did not affect citrate synthase activity from mitochondrial preparations and purified enzyme. The data indicate that D-Ser impairs the citric acid cycle activity via citrate synthase inhibition, therefore compromising energy metabolism production in cerebral cortex of young rats. Therefore, it is presumed that this mechanism may be involved at least in part in the neurological damage found in patients affected by disorders in which D-Ser metabolism is impaired, with altered cerebral concentrations of this D-amino acid.
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Affiliation(s)
- Angela Zanatta
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos No. 2600-Anexo, Porto Alegre, RS, Brazil
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Ohi K, Hashimoto R, Yasuda Y, Yoshida T, Takahashi H, Iike N, Fukumoto M, Takamura H, Iwase M, Kamino K, Ishii R, Kazui H, Sekiyama R, Kitamura Y, Azechi M, Ikezawa K, Kurimoto R, Kamagata E, Tanimukai H, Tagami S, Morihara T, Ogasawara M, Okochi M, Tokunaga H, Numata S, Ikeda M, Ohnuma T, Ueno SI, Fukunaga T, Tanaka T, Kudo T, Arai H, Ohmori T, Iwata N, Ozaki N, Takeda M. Association study of the G72 gene with schizophrenia in a Japanese population: a multicenter study. Schizophr Res 2009; 109:80-5. [PMID: 19237267 DOI: 10.1016/j.schres.2009.01.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 01/17/2009] [Accepted: 01/26/2009] [Indexed: 12/18/2022]
Abstract
G72 is one of the most widely tested genes for association with schizophrenia. As G72 activates the D-amino acid oxidase (DAO), G72 is termed D-amino acid oxidase activator (DAOA). The aim of this study is to investigate the association between G72 and schizophrenia in a Japanese population, using the largest sample size to date (1774 patients with schizophrenia and 2092 healthy controls). We examined eight single nucleotide polymorphisms (SNPs), which had been associated with schizophrenia in previous studies. We found nominal evidence for association of alleles, M22/rs778293, M23/rs3918342 and M24/rs1421292, and the genotype of M22/rs778293 with schizophrenia, although there was no association of allele or genotype in the other five SNPs. We also found nominal haplotypic association, including M15/rs2391191 and M19/rs778294 with schizophrenia. However, these associations were no longer positive after correction for multiple testing. We conclude that G72 might not play a major role in the risk for schizophrenia in the Japanese population.
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Affiliation(s)
- Kazutaka Ohi
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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25
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Amino acids: metabolism, functions, and nutrition. Amino Acids 2009; 37:1-17. [PMID: 19301095 DOI: 10.1007/s00726-009-0269-0] [Citation(s) in RCA: 1614] [Impact Index Per Article: 107.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2009] [Accepted: 03/01/2009] [Indexed: 02/06/2023]
Abstract
Recent years have witnessed the discovery that amino acids (AA) are not only cell signaling molecules but are also regulators of gene expression and the protein phosphorylation cascade. Additionally, AA are key precursors for syntheses of hormones and low-molecular weight nitrogenous substances with each having enormous biological importance. Physiological concentrations of AA and their metabolites (e.g., nitric oxide, polyamines, glutathione, taurine, thyroid hormones, and serotonin) are required for the functions. However, elevated levels of AA and their products (e.g., ammonia, homocysteine, and asymmetric dimethylarginine) are pathogenic factors for neurological disorders, oxidative stress, and cardiovascular disease. Thus, an optimal balance among AA in the diet and circulation is crucial for whole body homeostasis. There is growing recognition that besides their role as building blocks of proteins and polypeptides, some AA regulate key metabolic pathways that are necessary for maintenance, growth, reproduction, and immunity. They are called functional AA, which include arginine, cysteine, glutamine, leucine, proline, and tryptophan. Dietary supplementation with one or a mixture of these AA may be beneficial for (1) ameliorating health problems at various stages of the life cycle (e.g., fetal growth restriction, neonatal morbidity and mortality, weaning-associated intestinal dysfunction and wasting syndrome, obesity, diabetes, cardiovascular disease, the metabolic syndrome, and infertility); (2) optimizing efficiency of metabolic transformations to enhance muscle growth, milk production, egg and meat quality and athletic performance, while preventing excess fat deposition and reducing adiposity. Thus, AA have important functions in both nutrition and health.
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Hoffman HE, Jirásková J, Ingr M, Zvelebil M, Konvalinka J. Recombinant human serine racemase: Enzymologic characterization and comparison with its mouse ortholog. Protein Expr Purif 2009; 63:62-7. [DOI: 10.1016/j.pep.2008.09.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 08/29/2008] [Accepted: 09/04/2008] [Indexed: 10/21/2022]
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27
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Tsai GE, Lane HY, VanDenBerg CM, Liu YC, Tsai P, Jann MW. Disposition of D-Serine in Healthy Adults. J Clin Pharmacol 2008; 48:524-527. [DOI: 10.1177/0091270008314253] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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28
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Riley J, Sweeney W, Boulis N. Shifting the balance: cell-based therapeutics as modifiers of the amyotrophic lateral sclerosis–specific neuronal microenvironment. Neurosurg Focus 2008; 24:E10. [DOI: 10.3171/foc/2008/24/3-4/e9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
✓ Recent advances in the laboratory have improved the current understanding of neurobiological mechanisms underlying the initiating events and pathological progression observed in amyotrophic lateral sclerosis (ALS). Whereas initial studies have revealed the late-stage intracellular cascades contributing to neuronal dysfunction and cell death, more recently collected data have begun to elucidate the presence and importance of a “non–cell autonomous” component indicating that affected glial cell subtypes may serve distinct and required roles. Pharmacological interventions for ALS have largely been disappointing likely in part because they have failed to address either the proximate events contributing to neuronal dysfunction and death or the deleterious contributions of non-neuronal cells within the local microenvironment. Alternatively, cell-based therapeutics offer the potential of a multifaceted approach oriented toward the dual ends of protecting remaining viable neurons and attempting to restore neuronal function lost as a manifestation of disease progression. The authors review the evolving knowledge of disease initiation and progression, with specific emphasis on the role of affected glia as crucial contributors to the observed ALS phenotype. This basis is used to underscore the potential roles of cell-based therapeutics as modifiers of the ALS-specific microenvironment.
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Affiliation(s)
- Jonathan Riley
- 1Cleveland Clinic Foundation, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio
| | - Walter Sweeney
- 1Cleveland Clinic Foundation, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio
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Katane M, Hanai T, Furuchi T, Sekine M, Homma H. Hyperactive mutants of mouse D-aspartate oxidase: mutagenesis of the active site residue serine 308. Amino Acids 2008; 35:75-82. [PMID: 18235994 DOI: 10.1007/s00726-007-0627-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 10/25/2007] [Indexed: 10/22/2022]
Abstract
The role of Ser-308 of murine D-aspartate oxidase (mDASPO), particularly its side chain hydroxyl group, was investigated through the use of site-specific mutational analysis of Ser-308. Recombinant mDASPO carrying a substitution of Gly, Ala, or Tyr for Ser-308 was generated, and fused to either His (His-mDASPO), or glutathione S-transferase, His, and S (GHS-mDASPO) at its N-terminus. Wild-type His-mDASPO or GHS-mDASPO or their mutant derivatives were expressed in Escherichia coli and purified by affinity chromatography. All purified recombinant proteins had functional DASPO activity. The Gly-308 and Ala-308 mutants had significantly higher catalytic efficiency towards D-Asp and N-methyl-D-Asp, and a higher affinity for flavin adenine dinucleotide (FAD) compared to the wild-type enzyme. The Tyr-308 mutant had lower catalytic efficiency and binding capacity. These results suggest that the side chain hydroxyl group of a critical residue of mDASPO, Ser-308, down-regulates enzymatic activity, substrate binding, and FAD binding. This study provides information on the active site of DASPO that will considerably enhance our understanding of the biological significance of this enzyme.
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Affiliation(s)
- M Katane
- Laboratory of Biomolecular Science, School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
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Masmoudi-Kouki O, Gandolfo P, Castel H, Leprince J, Fournier A, Dejda A, Vaudry H, Tonon MC. Role of PACAP and VIP in astroglial functions. Peptides 2007; 28:1753-60. [PMID: 17655978 DOI: 10.1016/j.peptides.2007.05.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 05/22/2007] [Accepted: 05/24/2007] [Indexed: 11/30/2022]
Abstract
Astrocytes represent at least 50% of the volume of the human brain. Besides their roles in various supportive functions, astrocytes are involved in the regulation of stem cell proliferation, synaptic plasticity and neuroprotection. Astrocytes also influence neuronal physiology by responding to neurotransmitters and neuropeptides and by releasing regulatory factors termed gliotransmitters. In particular, astrocytes express the PACAP-specific receptor PAC1-R and the PACAP/VIP mutual receptors VPAC1-R and VPAC2-R during development and/or in the adult. There is now clear evidence that PACAP and VIP modulate a number of astrocyte activities such as proliferation, plasticity, glycogen production, and biosynthesis of neurotrophic factors and gliotransmitters.
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Affiliation(s)
- Olfa Masmoudi-Kouki
- INSERM U413, Laboratory of Cellular and Molecular Neuroendocrinology, France
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